1. Field of the Invention
The present invention relates to a device for stripping a fibrous web from a doffer in a carding machine for cotton and like materials, and more particularly, to a carded web stripping device having a suction roller which prevents winding of fibers around rollers and removes impurities from the web.
2. Description of the Prior Art
A fly comb has hitherto been well known in the art as a web stripping device on a carding machine. However, because of limitation of its speed in swinging movement, the fly comb cannot be applied to high-speed carding machines recently in use. Further, as such as fly comb strips the web by intermittent impacts during its swinging movement and causes a turbulence of air in its vicinity, it is difficult to obtain a satisfactory web having fibers disentangled and arranged in a parallel fashion.
To overcome such disadvantages of the fly comb, there has been provided a web stripping device in which a doffing roller having a mechanical stripping means such as a metallic wire in its periphery is provided adjacent a doffer and a plurality of rollers are placed between the doffer and a web collector. The rollers between the doffer and the web collector are, for example, a smooth roller or a roller having a relatively rough stripping means, depending on the purpose of the device. However, a stripping device of this type is complicated in construction and requires a wide space for accommodation of the rollers. Further, as the speed of rotation of the roller having the stripping means is increased, stripping of the web from the roller becomes difficult and fibers are wound around the roller, whereby much time is required for cleaning the roller to remove the fibers. If the web which is a thin flat mass of disentangled fibers, is strained to prevent winding of the fibers around the roller, its feeble edges are unduly stretched when it is pulled by the collector. Another disadvantage of the device is that it takes much time in the beginning of the operation to adjust the velocity ratio between the rollers and to feed the web successively through the rollers. Further, the waste fibers and impurities once separated from the web tend to stick again to the web under the influence of a revolving air flow created by rotation of the rollers and lower the quality of the sliver produced from the web.